U.S. patent number 10,500,694 [Application Number 15/635,770] was granted by the patent office on 2019-12-10 for chemical mechanical polishing apparatus and methods.
This patent grant is currently assigned to Applied Materials, Inc.. The grantee listed for this patent is Applied Materials, Inc.. Invention is credited to Rajeev Bajaj, Hung Chen, Terrance Y. Lee, Thomas H. Osterheld.
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United States Patent |
10,500,694 |
Bajaj , et al. |
December 10, 2019 |
Chemical mechanical polishing apparatus and methods
Abstract
A substrate polishing apparatus is disclosed that includes a
polishing platform having two or more zones, each zone adapted to
receive a different slurry component. A substrate polishing system
is provided having a holder to hold a substrate, a polishing
platform having a polishing pad, and a distribution system adapted
to dispense, in a timed sequence, at least two different slurry
components selected from a group consisting of an oxidation slurry
component, a material removal slurry component, and a corrosion
inhibiting slurry component. Polishing methods and systems adapted
to polish substrates are provided, as are numerous other
aspects.
Inventors: |
Bajaj; Rajeev (Fremont, CA),
Osterheld; Thomas H. (Mountain View, CA), Chen; Hung
(Sunnyvale, CA), Lee; Terrance Y. (Oakland, CA) |
Applicant: |
Name |
City |
State |
Country |
Type |
Applied Materials, Inc. |
Santa Clara |
CA |
US |
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Assignee: |
Applied Materials, Inc. (Santa
Clara, CA)
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Family
ID: |
51165467 |
Appl.
No.: |
15/635,770 |
Filed: |
June 28, 2017 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20170297163 A1 |
Oct 19, 2017 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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14143276 |
Dec 30, 2013 |
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61751688 |
Jan 11, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B24B
57/02 (20130101); H01L 21/67092 (20130101); H01L
21/30625 (20130101); B24B 37/044 (20130101); H01L
21/67075 (20130101); H01L 21/3212 (20130101) |
Current International
Class: |
B24B
37/04 (20120101); B24B 57/02 (20060101); H01L
21/321 (20060101); H01L 21/67 (20060101); H01L
21/306 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1458671 |
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Nov 2003 |
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CN |
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1495863 |
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May 2004 |
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CN |
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2000-176829 |
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Jun 2000 |
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JP |
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2000-308957 |
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Nov 2000 |
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JP |
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2004-511109 |
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Apr 2004 |
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JP |
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2006-261261 |
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Sep 2006 |
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JP |
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2012-076220 |
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Apr 2012 |
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JP |
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10-2007-0098321 |
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Oct 2007 |
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KR |
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200503875 |
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Feb 2005 |
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TW |
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200613092 |
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May 2006 |
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TW |
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WO 2010005702 |
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Jan 2010 |
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WO |
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Other References
Hsu et al., U.S. Appl. No. 13/944,204, titled "Chemical Mechanical
Polishing Retaining Ring Methods and Apparatus," filed Jul. 17,
2013. cited by applicant .
International Search Report and Written Opinion of International
Application No. PCT/US13/78313 dated Apr. 30, 2014. cited by
applicant .
Wang et al., U.S. Appl. No. 13/866,449, titled "Interconnect
Fabrication At an Integrated Semiconductor Processing Station,"
filed Apr. 19, 2013. cited by applicant .
Restriction Requirement of U.S. Appl. No. 14/143,276 dated Aug. 21,
2014. cited by applicant .
Aug. 26, 2014 Reply to Aug. 21, 2014 Restriction Requirement of
U.S. Appl. No. 14/143,276. cited by applicant .
Non-Final Office Action of U.S. Appl. No. 14/143,276 dated Sep. 11,
2014. cited by applicant .
Dec. 11, 2014 Reply to Sep. 11, 2014 Non-Final Office Action of
U.S. Appl. No. 14/143,276. cited by applicant .
Final Office Action of U.S. Appl. No. 14/143,276 dated Feb. 26,
2015. cited by applicant .
Amendment Submitted with RCE of U.S. Appl. No. 14/143,276, filed
May 26, 2015. cited by applicant .
International Preliminary Report on Patentability of International
Application No. PCT/US13/78313 dated Jul. 23, 2015. cited by
applicant .
Restriction Requirement of U.S. Appl. No. 14/341,762 dated Aug. 7,
2015. cited by applicant .
Oct. 7, 2015 Reply to Aug. 7, 2015 Restriction Requirement of U.S.
Appl. No. 14/341,762. cited by applicant .
International Search Report and Written Opinion of International
Application No. PCT/US2015/041856 dated Oct. 30, 2015. cited by
applicant .
Non-Final Office Action of U.S. Appl. No. 14/341,762 dated Nov. 6,
2015. cited by applicant .
Non-Final Office Action of U.S. Appl. No. 14/143,276 dated Nov. 25,
2015. cited by applicant .
Feb. 8, 2016 Reply to Nov. 6, 2015 Non-Final Office Action of U.S.
Appl. No. 14/341,762. cited by applicant .
Feb. 25, 2016 Reply to Nov. 25, 2015 Non-Final Office Action of
U.S. Appl. No. 14/143,276. cited by applicant .
Final Office Action of U.S. Appl. No. 14/341,762 dated May 18,
2016. cited by applicant .
Jul. 18, 2016 Reply to May 18, 2016 Final Office Action and Request
for Consideration Under the After Final Consideration Pilot Program
2.0 of U.S. Appl. No. 14/341,762. cited by applicant .
Applicant-Initiated Interview Summary of U.S. Appl. No. 14/341,762
dated Aug. 2, 2016. cited by applicant .
Final Office Action of U.S. Appl. No. 14/143,276 dated Aug. 4,
2016. cited by applicant .
Advisory Action and After Final Consideration Program Decision of
U.S. Appl. No. 14/341,762 dated Aug. 4, 2016. cited by applicant
.
Non-Final Office Action of U.S. Appl. No. 14/341,762 dated Oct. 14,
2016. cited by applicant .
Amendment Submitted with RCE of U.S. Appl. No. 14/143,276, filed
Dec. 5, 2016. cited by applicant .
Jan. 13, 2017 Reply to Oct. 14, 2016 Non-Final Office Action of
U.S. Appl. No. 14/341,762. cited by applicant .
International Preliminary Report on Patentability of International
Application No. PCT/US2015/041856 dated Feb. 9, 2017. cited by
applicant .
Final Office Action of U.S. Appl. No. 14/341,762 dated Feb. 15,
2017. cited by applicant .
Non-Final Office Action of U.S. Appl. No. 14/143,276 dated Feb. 28,
2017. cited by applicant .
Chinese Search Report of Chinese Application No. 201380070166.4
dated Jan. 13, 2017. cited by applicant .
Taiwan Search Report of Taiwan Application No. 103100864 dated Mar.
23, 2017. cited by applicant .
Osterheld et al., U.S. Appl. No. 15/624,682, titled "Chemical
Mechanical Polishing Apparatus and Methods," filed Jun. 15, 2017.
cited by applicant .
Advisory Action of U.S. Appl. No. 14/341,762 dated Jun. 27, 2017.
cited by applicant .
Non-Final Office Action of U.S. Appl. No. 15/624,682 dated Aug. 14,
2017. cited by applicant .
Notice of Abandonment of U.S. Appl. No. 14/341,762 dated Sep. 12,
2017. cited by applicant .
Nov. 14, 2017 Reply to Non-Final Office Action and Terminal
Disclaimer of U.S. Appl. No. 15/624,682. cited by applicant .
Final Office Action of U.S. Appl. No. 15/624,682 dated Apr. 17,
2018. cited by applicant .
Jun. 18, 2018 Reply to Apr. 17, 2018 Final Office Action of U.S.
Appl. No. 15/624,682. cited by applicant .
Japanese Office Action of Japanese Application No. 2015-552659
dated Sep. 11, 2018. cited by applicant .
Non-Final Office Action of U.S. Appl. No. 15/624,682 dated Dec. 19,
2018. cited by applicant .
Mar. 19, 2019 Reply to Dec. 19, 2019 Non-Final Office Action of
U.S. Appl. No. 15/624,682. cited by applicant.
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Primary Examiner: Olsen; Allan W.
Attorney, Agent or Firm: Fish & Richardson P.C.
Parent Case Text
RELATED APPLICATIONS
This application is a divisional of and claims priority to U.S.
patent application Ser. No. 14/143,276 filed Dec. 30, 2013, and
titled "CHEMICAL MECHANICAL POLISHING APPARATUS AND METHODS", which
claims priority to U.S. Provisional Application 61/751,688 filed
Jan. 11, 2013, and entitled "CHEMICAL MECHANICAL POLISHING
APPARATUS AND METHODS". Each of these applications is hereby
incorporated by reference herein in its entirety for all purposes.
Claims
The invention claimed is:
1. A method of polishing a substrate, comprising: providing a
substrate in a substrate holder; providing a polishing platform
having a moveable polishing pad; dispensing a first slurry
component into two or more first zones on the polishing pad; and
dispensing a second slurry component into one or more second zones
on the polishing pad, wherein the first and second slurry
components are different slurry components with one of the first
and second slurry components including an abrasive or etchant
without an oxidizer and another of the first and second slurry
components including an oxidizer without an abrasive and without an
etchant.
2. The method of claim 1, wherein the first slurry component
includes the abrasive or the etchant.
3. The method of claim 1, further comprising dispensing a rinsing
liquid onto the polishing pad.
4. The method of claim 1, further comprising dispensing a rinsing
liquid into a zone located between at least one of the two or more
first zones and at least one of the one or more second zones.
5. The method of claim 1, wherein dispensing the first slurry
component and the second slurry component comprises dispensing the
first slurry component and the second slurry component
concurrently.
6. The method of claim 1, wherein two or more first zones have
widths in a range of 2 mm to 50 mm.
7. A method of polishing a substrate, comprising: providing a
substrate in a substrate holder; providing a polishing platform
having a moveable polishing pad; and dispensing between the
polishing pad and the substrate, in a timed sequence, a first
slurry component into two or more first zones and a second slurry
component into one or more second zones, the first slurry component
having a different chemical composition than the second slurry
component with one of the first and second slurry components
including an abrasive or etchant without a corrosion inhibitor and
another of the first and second slurry components including a
corrosion inhibitor without an abrasive and without an etchant.
8. The method of claim 7, wherein the first slurry component
includes the abrasive or etchant.
9. The method of claim 7, further comprising dispensing a rinsing
liquid between the polishing pad and the substrate.
10. The method of claim 7, further comprising dispensing a rinsing
liquid into a zone located between at least one of the two or more
first zones and at least one of the one or more second zones.
11. The method of claim 7, wherein two or more first zones have
widths in a range of 2 mm to 50 mm.
12. A method of polishing a substrate, comprising: providing a
plurality of individual slurry component supplies including a first
slurry component supply configured to supply an oxidizer without an
etchant, without an abrasive and without a corrosion inhibitor, a
second slurry component supply configured to supply an abrasive or
etchant without a oxidizer and without a corrosion inhibitor, and a
third slurry component supply configured to supply a corrosion
inhibitor without an oxidizer, without an etchant and without an
abrasive; dispensing a first slurry component onto two or more
first zones of a polishing platform via a distribution system
configured to dispense the first slurry component from the
plurality of individual slurry component supplies; and dispensing a
second slurry component onto one or more second zones of the
polishing platform via the distribution system.
13. The method of claim 12 wherein the first slurry component and
the second slurry component are provided in the two or more first
zones and the one or more second zones concurrently.
14. The method of claim 12, further comprising dispensing a rinsing
liquid onto the polishing platform.
15. The method of claim 12, further comprising dispensing a rinsing
liquid into a zone located between at least one of the two or more
first zones and at least one of the one or more second zones.
Description
FIELD
The present invention relates generally to semiconductor device
manufacturing, and more particularly to methods and apparatus
adapted to polish a substrate surface.
BACKGROUND
Within semiconductor substrate manufacturing, a chemical mechanical
polishing (CMP) process may be used to remove various layers, such
as silicon, oxides, copper, or the like. Such polishing (e.g.,
planarization) may be accomplished by pressing a rotating substrate
held in a holder (e.g., polishing head or carrier) against a
rotating polishing pad while a slurry is applied ahead of the
substrate (e.g., patterned wafer). The slurry is commonly made up
of a mixture of oxidants, metal oxide abrasive particles, etchants,
complexing agents, and corrosion inhibitors. Thus, during
polishing, a continuous process of oxidation by oxidants and
material removal by abrasive particles and etchants is carried out
by the slurry and polishing process. During this polishing process,
precise control of the amount of material removal from the
substrate is sought. However, given the limitations of existing
processes, it is difficult to achieve uniformity, especially for
removal of small layer thicknesses.
Accordingly, improved polishing apparatus, systems, and methods are
sought.
SUMMARY
In a first aspect, a substrate polishing apparatus is provided. The
substrate polishing apparatus includes a polishing platform having
two or more zones, each zone adapted to contain a different slurry
component.
In another aspect, a substrate polishing system is provided. The
substrate polishing system includes a substrate holder adapted to
hold a substrate, and a polishing platform having a moveable
polishing pad with two or more zones, each zone operable to receive
a different slurry component.
In yet another aspect, a method of processing a substrate is
provided. The method includes providing a substrate in a substrate
holder, providing a polishing platform having a moveable polishing
pad, and dispensing a different slurry component into two or more
zones on the polishing pad.
In another aspect, a substrate polishing system is provided. The
substrate polishing system includes a substrate holder adapted to
hold a substrate, a polishing platform having a polishing pad
moveable relative to the substrate, and a distribution system
adapted to dispense, in a timed sequence, at least two different
slurry components selected from a group consisting of an oxidation
slurry component, a material removal slurry component, and a
corrosion inhibiting slurry component.
In yet another aspect, a method of processing a substrate is
provided. The method includes providing a substrate in a substrate
holder, providing a polishing platform having a moveable polishing
pad, and dispensing between the polishing pad and the substrate, in
a timed sequence, two or more slurry components each having a
different chemical composition.
Other features and aspects of the present invention will become
more fully apparent from the following detailed description of
example embodiments, the appended claims, and the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A illustrates a schematic top view of a linear substrate
polishing apparatus according to embodiments.
FIG. 1B illustrates a schematic cross-sectioned side view of a
linear substrate polishing apparatus according to embodiments taken
along section line 1B-1B of FIG. 1A.
FIG. 1C illustrates a schematic cross-sectioned side view of a
linear substrate polishing apparatus according to embodiments taken
along section line 1C-1C of FIG. 1A.
FIG. 2A illustrates a schematic top view of a rotary substrate
polishing apparatus according to embodiments.
FIG. 2B illustrates a schematic side view of a rotary substrate
polishing apparatus according to embodiments.
FIG. 3A illustrates a top view of a slurry distributor according to
embodiments.
FIG. 3B illustrates a side view of a slurry distributor according
to embodiments.
FIG. 3C illustrates a first end view of a slurry distributor
according to embodiments.
FIG. 3D illustrates a second end view of a slurry distributor
according to embodiments.
FIGS. 3E-3G illustrate various cross section view of a slurry
distributor according to embodiments.
FIG. 4 illustrates a flowchart of a method of polishing a substrate
according to embodiments.
FIG. 5 illustrates a flowchart of a method of polishing a substrate
according to embodiments.
FIG. 6 illustrates a graph of phases (e.g., pulses) of a method of
polishing a substrate according to embodiments.
FIG. 7 illustrates a graph of phases (e.g., pulses) of another
method of polishing a substrate according to embodiments.
DESCRIPTION
Embodiments described herein relate to apparatus, systems and
methods useful for, and adapted to, polishing a surface of a
substrate in semiconductor device manufacturing.
Prior systems have utilized a slurry of mixed slurry components.
The components of the slurry are adapted to accomplish various
processes on the substrate, such as the process of oxidation of the
substrate surface by oxidants and material removal by abrasive
particles and etchants. In a typical small removal process adapted
to remove less than about 250 Angstroms, the across the wafer
removal variations may be as high as 50%-100% of the film thickness
that is removed. With advancing technology, thinner and thinner
films are being applied and may be undergo polishing. For example,
films used in the formation of front end structures, such as inlaid
metal gates and the like are very thin. As these films are provided
in the device structures, it is desired that these thin films be
removed with a relatively high degree of uniformity and control.
Accordingly, as films get thinner, less material removal is
accomplished by the CMP, and more precision is desired in the
removal process. In the extreme case of atomic layer deposition
(ALD), where film thickness is measured in atomic layers (e.g.,
Angstroms), the material removal precision is also desired to be on
the order of an atomic layer.
Therefore, there is a need for a polishing apparatus and methods
that enables removal of thin films, wherein such removal is
accomplished with very high uniformity. Furthermore, it is desired
that the method can offer precise control of the removal process,
i.e. the relative amount of removal. In one aspect, embodiments of
the invention physically separate the slurry components. This may
be used to provide more precise control over amount of material
removal. By physically (e.g., spatially) separating the slurry
components, the polishing process may be provided with distinct
breaks (e.g., formed as physical zones of slurry components having
differing chemical composition) between two or more of the slurry
components (e.g., accomplishing oxidation, material removal, and
corrosion inhibition).
For example, in one or more embodiments, a polishing platform
(e.g., comprising a pad support and pad) may be separated to have
two or more zones, wherein each zone is adapted to contain a
different slurry component. Each slurry component may have a
different chemical composition. During polishing, the substrate may
be moved rastered (e.g., translated) across the zones wherein each
adjacent zone includes a different slurry component. Running one
cycle across the zones, in sequence, may be used to effectively
remove one atomic layer, for example. Total material removal can be
precisely controlled by managing the number of cycles. Removal may
be controlled on an atomic level.
In one or more embodiments, the polishing surface is separated
(e.g., broken up) into multiple zones, wherein each zone contains
an individual slurry component that performs one of an oxidation,
material removal, or corrosion inhibition process. By rastering
(e.g., scanning) across these separated zones, high cycle counts
can be achieved within reasonable total polish time. For example,
within an oxidation zone containing the oxidation slurry component,
oxidants function to oxidize the surface layer of substrate. This
oxidation process may be self-limiting, since only a surface layer
is exposed to oxidants. Within the material removal zone
containing, for example, the removal and etchant slurry component,
abrasives and etchants attack the previously-oxidized surface
layer. The material removal zone may be adjacent to the oxidation
zone. This material removal process may also be self-limiting,
since only the oxidized layer is removed. A corrosion inhibiting
zone containing a corrosion inhibiting slurry component (e.g.,
including corrosion inhibiters) operates on the previously abraded
surface layer to limit corrosion thereof. The corrosion inhibiting
zone may be provided adjacent to the oxidation zone.
In another aspect, rather than being separated physically, the
application of the slurry components are separated in time. Thus,
in one aspect, embodiments of the invention disclose a polishing
process (e.g., a film removal process), which utilizes multi-step
reactions to affect uniform film removal. In particular,
embodiments of the invention separate the slurry components in time
by introducing them separately and in a timed sequence. This may be
used to provide more precise control over amount of material
removal. This multi-step polishing process can be applied to any
application where the CMP involves competing reactions.
Thus, in this aspect, the polishing process will have distinct
breaks (e.g., separations in time) between administering of the
various slurry components used to accomplish oxidation, material
removal, and/or corrosion inhibition processes. In one or more
embodiments, the oxidiation slurry component may be first
introduced in time, followed by a material removal slurry component
(e.g., containing abrasives and/or etchants). This may be followed
in sequence by introducing a corrosion inhibitor slurry component
in some embodiments. The sequence may be followed by introduction
of a rinsing liquid (e.g., de-ionized (DI) water) in some
embodiments. In other embodiments, the rinsing liquid may be
introduced between the various slurry introductions phases. These
slurry components may be administered between the substrate and the
polishing pad during the polishing process, as will be further
explained herein.
These and other aspects of embodiments of the invention are
described below with reference to FIGS. 1A-7 herein.
FIGS. 1A-1C illustrate various views of a substrate polishing
apparatus 100 and components thereof. The substrate polishing
apparatus 100 is adapted to hold and polish a substrate 101 as will
be apparent from the following description. The substrate polishing
apparatus 100 includes a polishing platform 102 having two or more
physical zones, such as first zone 104, second zone 106, and third
zone 108. The two or more zones (e.g., 104, 106, and 108) are
adapted to contain a different slurry component having a different
chemistry (chemical composition). The two or more zones may be
arranged across a width "W" of the platform 102. In the depicted
embodiment, nine zones are shown. However, more or less numbers of
zones may be provided. There may be multiple zones that are
non-adjacent, but that contain a slurry component having the same
chemistry. In the depicted embodiment, the platform 102 comprises a
linear polishing platform wherein the two or more zones are
arranged across a width "W" of a pad 109 and that extend along the
length "L" of the pad with the length L being substantially longer
than the width W. In the depicted embodiment, the pad 109 of the
platform 102 moves linearly as indicated by directional arrow
110.
During the polishing method, various slurry components, such as
slurry component 1, slurry component 2, and slurry component 3 may
be applied to the pad 109 by a distributor 112. The distributor 112
may have any suitable internal structure capable of dispensing the
slurry components to the two or more zones (e.g., to zones 104,
106, 108). The slurry component 1, slurry component 2, and slurry
component 3, for example, may be received from slurry component
supplies 114, 116, 118, respectively. More or less numbers of
slurry components may be provided. The supply of slurry components
to the distributor 112 may be accomplished by a distribution system
having one or more suitable pumps or other flow control mechanisms
115. "Slurry component" as used herein means a processing medium
that is adapted to carry out one or more designated polishing
functions. In some embodiments, a rinsing liquid (e.g., de-ionized
water) may be provided from the rinsing liquid source 123 and
inserted between two or more of the zones, such as between zone 104
and 106, or between 106 and 108, or between both zones 104 and 106
and zones 106 and 108. Any suitable construction of the distributor
112 may be used to accomplish this separation of the zones 104,
106, 108 by a rinsing liquid zone.
For example, slurry component 1 may comprise a material adapted to
execute a surface modification function, such as oxidation or other
surface modification such as the formation of a nitride, bromide,
chloride, or hydroxide containing later. Slurry component 1 may
contain a liquid carrier such as purified water, and an oxidant
such as hydrogen peroxide, ammonium persulfate, or potassium
iodate. Other surface modifying materials may be used. Slurry
component 1 may be supplied to the first zone 104 of the pad 109
from the component supply 1 114 through a first channel 119A (FIG.
3G) of the distributor 112, for example.
Slurry component 2 may comprise a material adapted to execute a
material removal function. Slurry component 2 may contain a liquid
carrier such as purified water, and abrasive media such as silicon
dioxide or aluminum oxide. The abrasive may have an average
particle size between about 20 nanometers and 0.5 microns. Other
particle sizes may be used. Slurry component 2 may also include an
etchant material such as carboxylic acid, or an amino acid. Other
etchant or complexing agent materials may be used. Slurry component
2 may be supplied from the component supply 2 116 to the second
zone 106 of the pad 109 by a second channel 119B (FIG. 3F) of the
distributor 112, for example.
In one or more embodiments, slurry component 3 may comprise a
material adapted to execute a corrosion inhibition function. Slurry
component 3 may contain a liquid carrier such as purified water,
and corrosion inhibitor such as benzotriazole, or 1,2,4 Triazole.
Slurry component 3 may be supplied from the component supply 3 118
to the third zone 108 of the pad 109 by a third channel 119C (FIG.
3E) of the distributor 112, for example.
The zones 104, 106, 108 may be arranged in a side by side fashion
and may each have a width of between about 2 mm and 50 mm. The
widths may be the same as or different from each other. Other
widths may be used.
In one or more embodiments, a distribution system including a
distributor 112 is adapted to dispense into the two or more zones
(e.g., zone 104, 106) at least two different slurry components. The
slurry components may be selected from a group consisting of a
surface modification slurry component, and a material removal
slurry component, as discussed above.
In one or more embodiments, the distributor 112 may be formed as a
unitary component and may be positioned adjacent to the pad 109
(e.g., just above the pad 109). The distributor 112 may provide
delivery of the slurry components concurrently through two or more
outlets (e.g., through outlets 121A, 121B, and 121C). For example,
as shown in FIG. 3A-3G, the distributor 112 may be part of a
distribution system that may include multiple channels, such as a
first channel 119A extending along a length of the distributor body
117. First channel 119A is adapted to distribute the slurry
component 1 from component 1 supply 114 to one or more first
distribution outlets 121A that are fluidly coupled to the first
channel 119A along its length.
The distributor 112 may also include a second channel 119B
extending along the length of the distributor body 117 and adapted
to distribute the slurry component 2 from component 2 supply 116 to
one or more second distribution outlets 121B that are fluidly
coupled to the second channel 119B along its length.
The distributor 112 may also include a third channel 119C extending
along the length of the distributor body 117 and adapted to
distribute the slurry component 3 from component 3 supply 118 to
one or more second distribution outlets 121C that are fluidly
coupled to the third channel 119C along its length. Other channels
and interconnected outlets may be provided to disburse other slurry
components and/or a rinsing liquid.
In some embodiments, the rinsing liquid may be received in a
separate separation zone to separate the disbursed slurry
components. The outlets 121A, 121B, 121C may have a diameter of
less than about 5 mm, or between about 1 mm and 15 mm in some
embodiments. A pitch (e.g., spacing between the adjacent outlets)
may be less than about 50 mm, less than about 25 mm, or even less
than about 10 mm in some embodiments. In some embodiments, the
pitch may be between about 2 mm and 50 mm. Other diameters and
pitches may be used.
In other embodiments, the distributor may be comprised of separate
distributor heads, one for each slurry component that may be
arranged at different spatial locations on the pad 109. A rinsing
liquid (e.g., DI water) may be delivered through some or all of the
outlets 121A-121C, or through separate outlets specifically
designed for the rinsing liquid. Rinsing liquid may be provided
from rinsing liquid supply 123 to some or all of each of the
outlets 121A-121C by controlling valve 119S. Optionally, the
rinsing liquid may be provided by a separate distributor head or
separate outlets from the distributor 112.
In another embodiment, the distributor may be included in the pad
support 127 of the platform 102. In this embodiment, the slurry
components 1, 2, 3 may be disbursed to the various zones 104, 106,
and 108 from underneath the pad 109. The pad support 127 may
include holes like the outlets 121A-121C in distributor 112 being
arranged across the width of the pad 109. Each hole may be fluidly
coupled to one of the slurry component supplies 114, 116, 118. The
various separated slurry components 1, 2, 3 may pass though the
holes and wick through the pad 109 containing an internal porous
structure of connected open pores as the pad 109 is rotated on the
rollers 124, 126. The wicking provides the slurry components 1, 2,
3 to the one or more zones 104, 106, 108, respectively. Rinsing
liquid may also be disbursed through some or all of the holes.
Again referring to FIGS. 1A-1C, as the slurry components are being
supplied to the zones 104, 106, 108 of the pad 109, a substrate
holder 120 of the substrate polishing apparatus 100 may be rotated.
Substrate holder 120 is adapted to hold the substrate 101 in
contact with the pad 109 and rotate the substrate 101 as the
polishing takes place. Other motions may be provided in addition or
in place of the rotation, such as orbital motion. Rotational speed
may be between about 10-150 RPM, for example. Rotation may be
accomplished by driving the holder 120 with a holder motor 122. Any
suitable motor may be used. An applied pressure on the substrate
101 during polishing may be between about 0.1 psi and 1 psi, for
example. Any suitable conventional mechanism for applying the
pressure may be used, such as a spring-loaded mechanism or other
suitable vertically-acting actuator. Other rotational speeds and
pressures may be used. Substrate holders (also referred to as
retainers or carrier heads) are described in U.S. Pat. No.
8,298,047; U.S. Pat. No. 8,088,299; U.S. Pat. No. 7,883,397; and
U.S. Pat. No. 7,459,057, issued to the present assignee, for
example.
As the slurry components 1, 2, 3 are applied to the respective
zones 104, 106, 108, the pad 109 may be moved in the direction of
the arrow 110. The linear speed of movement of the pad 109 in the
direction of arrow 110 may be between about 40 cm/sec and about 600
cm/sec, for example. Other speeds may be used. The pad 109, as best
shown in FIGS. 1B and 1C, may be provided in the form of a
continuous or endless belt. The pad 109 may be supported at its
ends by first and second rollers 124, 126 (e.g., cylindrical
rollers) and underneath the top portion of the pad 109 by a pad
support 127 spanning the width of the pad 109. Rollers 124, 126 may
be supported for rotation on a frame 128 by bearings or bushings,
or other suitable low friction devices, for example. One of the
rollers, such as roller 126, may be coupled to a pad drive motor
130 which may be driven at the appropriate rotational speed to
accomplish the linear polishing speed of the pad 109 described
above. Pad support 127 may also be coupled to the frame 128 at one
or more locations and may support the upper portion of the pad 109
underneath some or most of the length L of upper surface of the pad
109.
In addition to the rotation of the substrate holder 120, and the
motion of the pad 109, the holder 120 may be translated in the
direction of directional arrow 132. The translation may be an
oscillation back and forth along the transverse direction 132,
generally perpendicular to the linear motion of the pad 109.
Translation may be caused by any suitable translation motor 134 and
drive system (not shown) that moves the substrate holder 120 back
and forth along a support beam 136. The drive system adapted to
accomplish the translation may be a rack and pinion, chain and
sprocket, belt and pulley, drive and ball screw, or other suitable
drive mechanism. In other embodiments, an orbital motion may be
provided by a suitable mechanism. The rotation of the pad 109,
rotation and translation (e.g., oscillation) of the substrate
holder 120, and the distribution flow of the slurry components 1, 2
and 3 and rinsing liquid 123 may be controlled by controller 138.
Controller 138 may be any suitable computer and connected drive
and/or feedback components adapted to control such motions and
functions.
The pad 109 may be made of a suitable polishing pad material, for
example. The pad 109 may be a polymer material, such as
polyurethane, and may have open surface porosity. Surface porosity
may be open porosity and may have an average pore size of between
about 2 microns and 100 microns, for example. Pad may have a length
L, as measured between the centers of the rollers 124, 126, of
between about 30 cm and 300 cm, for example. Other dimensions may
be used.
FIGS. 2A and 2B illustrate various views of an alternative
embodiment of a substrate polishing apparatus 200 and components
thereof. As before, the substrate polishing apparatus 200 is
adapted to hold and polish a substrate 101 as will be apparent from
the following description. The substrate polishing apparatus 200
includes a polishing platform 202 having a pad 209 and a pad
support 227 (e.g., a platen). The polishing platform 202 has two or
more physical zones, such as first zone 204, and second zone 206,
and even a third zone 208. Zones 204, 206, 208 in this embodiment
are arranged as concentric annuli, and the platform 202 is
rotatable.
Each zone 204, 206, 208 is adapted to contain a different slurry
component having a different chemistry, such as slurry components
1-3 described above. The slurry components may be dispensed to the
various zones 204, 206, 208 by a distributor 212 coupled to the
component supplies 114, 116, 118, via valves or other flow control
mechanism as commended by controller 238 as described before. The
two or more zones 204, 206, 208 may be arranged across a diameter
"D" of the platform 202. The width of each annular zone may be the
same or different and of a width, and may be as described above. In
the depicted embodiment, nine annular zones are shown. However,
more or less numbers of zones may be provided. Furthermore, there
may be multiple zones that are not adjacent to each other, but that
contain a slurry component having a same chemistry (e.g., chemical
composition). For example, each of the zones labeled 204 may
receive and contain the same slurry chemistry. Each of the zones
labeled 206 may receive and contain the same slurry chemistry, and
each of the zones labeled 208 may receive and contain the same
slurry component chemistry. However, the chemistries in each of the
zones 204, 206 and 208 may have different slurry component
chemistries as compared to each other.
In the depicted embodiment, the platform 202 comprises a rotary
polishing platform wherein the two or more zones (e.g., zones 204,
206 or 204, 206 and 208) are arranged across a diameter D the pad
209. The platform 202 and pad 209 may be rotated in the direction
of directional arrow 210 at rotational speed of between about 10
and about 200 RPM by a platform motor 230. As before, the substrate
holder 220 may be rotated by a suitable holder motor 222 to rotate
the substrate 101 as the polishing takes place. Rotational speed of
the holder 220 may be between about 10 RPM-200 RPM, for example.
Similarly, the holder 220 may be translated (e.g., oscillated) back
and forth along the transverse direction 232, generally
perpendicular to the tangential motion of the pad 209. Translation
may be caused by any suitable translation motor 234 and drive
system (not shown) as described above.
An applied pressure on the substrate 101 during polishing may be as
discussed above, for example. Any suitable conventional mechanism
for applying the pressure may be used, such as a spring-loaded
mechanism or actuator. Other rotational speeds and pressures may be
used. Substrate holder 220 may be as described in U.S. Pat. No.
8,298,047; U.S. Pat. No. 8,088,299; U.S. Pat. No. 7,883,397; and
U.S. Pat. No. 7,459,057, for example.
FIG. 4 illustrates a method 400 of processing a substrate (e.g.,
substrate 101), and in particular a method of polishing a surface
(e.g., a front side or backside surface) of a substrate 101 (e.g.,
a patterned or unpatterned wafer). The method 400 includes, in 402,
providing a substrate in a substrate holder (e.g., substrate holder
120, 220), providing, in 404, a polishing platform (e.g., polishing
platform 102, 202) having a moveable polishing pad (e.g., polishing
pad 109, 209), and, in 406, dispensing a different slurry component
into two or more zones (e.g., zones 104, 106, 108) on the polishing
pad. The polishing pad may be of the linear moving version 109 or
rotationally moving version 209. The slurry components may be
disbursed to the zones (e.g., zones 104, 106, 108) above the pad
109 or below the pad 109 (e.g., by wicking or other capillary
action).
In another aspect, a substrate polishing system is provided as
described in either of FIGS. 1A-1C or 2A and 2B. The substrate
polishing system 100, 200 includes a polishing holder 120, 220
adapted to hold a substrate 101, a polishing platform 102, 202
having a polishing pad 109, 209 moveable relative to the substrate
101, and a distribution system adapted to dispense at least two
different slurry components selected from a group consisting of an
oxidation slurry component, a material removal slurry component,
and a corrosion inhibiting slurry component. In this aspect, rather
than being distributed into zones arranged across the width W or
diameter D of the pad 109, 209, the two or more slurry components
are dispensed in a timed sequence, one after another.
In accordance with this aspect, a first slurry component selected
from the group consisting of an oxidation slurry component, a
material removal slurry component, and a corrosion inhibiting
slurry component is first dispensed onto the pad (e.g., pad 109,
209). After a predetermined amount of time has elapsed, the supply
of the first slurry component is stopped, and a second slurry
component selected from the group consisting of an oxidation slurry
component, a material removal slurry component, and a corrosion
inhibiting slurry component is then dispensed onto the pad (e.g.,
pad 109, 209). After another predetermined amount of time has
elapsed, the supply of the second slurry component is stopped, and
a third slurry component selected from the group consisting of an
oxidation slurry component, a material removal slurry component,
and a corrosion inhibiting slurry component may then dispensed onto
the pad (e.g., pad 109, 209). After a third predetermined amount of
time has elapsed, the timed sequence may start over again by again
dispensing the first slurry components. The sequence may be
repeated as many times as necessary to accomplish the desired
results, such as a desired amount of film removal. Following the
polishing sequence, the pad 109, 209 may be rinsed by supplying
rinsing liquid thereto.
FIGS. 5 and 6 illustrate another method 500 of polishing a
substrate. The method 500 includes, in 502, providing a substrate
(e.g., substrate 101) in a substrate holder (e.g., holder 120,
220), and, in 504, providing a polishing platform having a moveable
polishing pad. In 506, the method includes dispensing, in a timed
sequence, two or more slurry components each having a different
chemical composition between the polishing pad and the
substrate.
As shown in FIG. 6, the slurry components may be dispersed between
the pad (e.g., pad 109, 209) and the substrate 101 in a timed
sequence as shown. In a first time increment 650, a first slurry
component (e.g., an oxidizing slurry component) may be supplied.
This is followed by a second slurry component (e.g., a material
removal slurry component) for a second time increment 651. The
chemical composition of the first and second slurry components are
different. This may be followed by providing a third slurry
component (e.g., a corrosion inhibiting slurry component) for a
third time increment 652. Two or more of these dispensing phases
may be repeated in 653-655. Other phases may be performed in
addition or in substitution thereof. The three- or more dispense
sequences may be repeated over and over as many times are desired
on a single substrate. This may be performed while the substrate is
being oscillated and rotated against the moving pad (e.g., pad 109,
209) as described above. After these polishing phases are
completed, the pad (e.g., pad 109, 209) may undergo a rinsing phase
wherein the pad (e.g., pad 109, 209) may be supplied with a rinsing
liquid (e.g., DI water or other inert liquid solution) in 656. The
disbursing of the rinsing liquid (e.g., de-ionized water) may be
used to dilute the last applied chemistry. The method 500 may then
stop, a new substrate may be placed in the substrate holder (e.g.,
substrate holder 120, 220), and the described method 500 may be
implemented on the second substrate starting at 657.
Each of the phases may take between about 1 second and about 60
seconds. Other time lengths may be used. Some of the pulses may be
less than 1 second. Each phase may be of the same or a different
length. Some of the slurry components may be combined in some
embodiments to institute more than one processing phase in a single
pulse. For example, an oxidation and corrosion inhibitor phase may
be combined as one slurry component and provided as one pulse in
some embodiments. In other embodiments, a complexing agent may be
combined in a single pulse with an abrasive (e.g., a metal oxide
abrasive). The oxidizing agent may be hydrogen peroxide. The
corrosion inhibitor may be triazole. The complexing agent may be an
organic acid, organic acid salt, or an amino acid. Other types of
oxidizing agents, corrosion inhibitors, complexing agents, and
abrasives may be used.
FIG. 6 illustrates another embodiment of a method 600 utilizing a
series of slurry components that are disbursed in a timed sequence
(e.g., as pulses of individual slurry components). The use of
time-separated introduction of polishing chemistry allows for
increased flexibility in use of chemical agents (e.g., two or more
slurry components). For example, oxidation chemistries are
generally self-limiting. A surface film may be oxidized to a depth
of about 20 angstroms and then stopped. By separating the slurry
components in time, more aggressive oxidation chemistries could be
used where the depth of oxidation may be controlled by the length
of the pulse of chemical slurry component supplied to the
substrate.
In particular, individual phases may be instituted to affect
specific reactions to form a modified layer on the surface of the
substrate. In some conventional material removal processes, systems
use slurry additives which may suppress removal at lower polishing
pressures. These prior polishing systems may provide better control
of within die (WID) thickness because removal rates drops
dramatically once topography has been removed. As a result,
topography in regions of a die with low density is quickly removed
and then the dielectric removal stops while topography removal in
other regions of the die continues to polish until they are
planarized. However, these systems suffer from very low removal
rates (by design) once the main topography has been planarized.
They may also suffer from large features being incompletely
removed. A multi-step method according to an aspect of the
invention having phased (e.g., timed) introduction of the slurry
components (e.g., additive, abrasive without additive, and possibly
interspersed and/or followed by a rinse) may be use to overcome
these previous limitations. For example, the additive could be
first introduced, followed by an abrasive solution which dilutes
the additive and enables limited film removal. Additional removal
could be accomplished by introduction of rinse which may quickly
dilute the additive and allows limited removal of film until the
charge of abrasive slurry component is exhausted.
An example of the multi-step method and system is provided below.
The method may be useful for metal film removal, and may involve an
oxidation phase involving film oxidation, and a phase of inhibitor
adsorption and complexing agent aided abrasion of the oxidized
surface, which are executed in a serial manner to achieve film
removal per reaction cycle. In this embodiment, each of the slurry
components may be dispersed between the pad (e.g., pad 109, 209)
and the substrate 101 in a timed sequence, but with a rinsing phase
being instituted between the disbursement of each slurry component,
as shown in FIG. 7. Thus, each pulse of a slurry component (e.g.,
oxidizing, inhibitor, complexing agent, material removal agent) may
be separated by a pulse of a rinsing agent (e.g., DI water) to
rinse the surface of the pad (e.g., pad 109, 209) and substrate
101.
In particular, in a first time increment 650, a first slurry
component (e.g., an oxidizing slurry component) may be supplied.
This is followed by a rinse in 657. Then a second slurry component
(e.g., a material removal slurry component) may be disbursed for a
second time increment 652. This may be followed by another rinse in
657. The chemical composition of the first and second slurry
components are different. This second rinse 657 may be followed by
a third slurry component (e.g., a corrosion inhibiting slurry
component) for a third time increment 653. This may be followed by
another rinse in 657. After this sequence is completed, it may be
repeated again on the same substrate 101 as many times as desired
to achieve the desired material removal, or a new substrate may be
inserted in the substrate holder (e.g., 120, 220) and polishing of
the substrate by the method 700 may commence on the new substrate.
The times may be the same or different for each phase of the
polishing process.
Other steps may be used in the sequence, such as an inhibitor
adsorption phase, and complexation-abrasion phase. Two or more of
the phases may be combined in some embodiments. The relative
duration of each phase may be determined based on reaction kinetics
of that particular phase. For example, an oxidation phase may be
relatively short for copper polish, while it may be relatively long
for polishing ruthenium or more noble metals. The pulse duration of
a corrosion inhibitor phase (including inhibitor adsorption) may
also be varied in length based on the kinetics of adsorption.
Likewise, a complexation-abrasion phase may be varied in length
based on the kinetics thereof. In some embodiments, a pulse of an
oxidizing slurry component (e.g., an oxidizing solution) may be
followed by a pulse of a corrosion inhibitor slurry component
(e.g., an inhibitor solution), and then followed by a pulse of a
complexing slurry component (e.g., a complexing agent). These
sequenced pulses may be provided while the substrate 101 is being
pressed against a moving surface of the pad (e.g., pad 109,
209).
Another example of a phased instruction of the slurry components in
a timed sequence is as follows. A copper film removal process is
provided wherein a first pulse of combined slurry component of an
oxidizer and inhibitor solution are followed by a separate pulse of
a complexing agent, while the substrate (e.g., wafer) is being
pressed against a moving surface of the pad (e.g., pad 109, 209) as
described herein. In some embodiments, the pulse of combined slurry
components of oxidizer and inhibitor solution and the separate
pulse of complexing agent may be interspersed by a rinsing pulse of
a rinsing liquid. Optionally, the rinse pulse may be at the end of
the two-phase sequence.
In another method embodiment adapted to metal oxide film polishing
and removal, a two-phase method includes a first pulse of an
oxidizing slurry component that may be followed by a separate
sequential pulse of a combined slurry component having a metal
oxide abrasive and a complexing agent. Optionally, the complexing
agent slurry component and the metal oxide abrasive slurry
component may be instituted as separated phases one after the other
in a three-phase polishing process. A rinsing phase may be
instituted between the phases or at the end of the sequence.
One significant advantage of the time sequence introduction of
slurry components is that each step or pulse may be self-limiting,
which may lead to relatively more uniform removal of even small
thicknesses, particularly less than 500 Angstroms, and especially
less than 200 Angstroms. For example, once a surface oxidation
phase of a surface (e.g., a copper surface) is completed to several
atomic layers (between about 25-30 Angstroms), the oxidation rate
may slow dramatically. Consequently, when the complexation-abrasion
phase is next executed, film removal may be automatically limited
to about 25 to 30 Angstroms, regardless of the length of the phase
and film removal uniformity may be made to be relatively
independent of removal rate.
In each of the described methods herein, the distribution of the
slurry components may be provided by the systems and apparatus
described herein. Optionally, other suitable systems adapted to
carry out a timed sequence delivery of the slurry components, and
possibly a rinse, may be used. Accordingly, while the present
invention has been disclosed in connection with example embodiments
thereof, it should be understood that other embodiments may fall
within the scope of the invention, as defined by the following
claims.
* * * * *